Global Variables

If you want to access same variable in multiple functions, you declare it as global var1 in your program.

Global variables can be read from all the functions but if you need to modify them, you need to declare them again in that function. Why? So that you don't inadvertently cause cascading effect. It's a preventive measure.

But then how are we able to read the variables w/o declaring them? It's a friendly feature. Python looks for local variables and if they are not found; it looks for any global variable. Since you're just trying to read the variable; it won't (hopefully) be a costly mistake.

Merge excel cell values ; Retain Boundaries

I'm working with excel workbooks for more than 6 hours a day. I needed a quick way to consolidate values of selected cells of a column in the top most row.
e.g.
To merge values of cells 41 to 45 of column B, select the cells and hit the macro. All the values will be consolidated in cell 41.

Sub concate_cell_values()
' This macro consolidates the values
' of the "selected" cells in the top most cell
' Respects cell boundaries

Dim Rng1 As Range
Dim op As String
Dim col, ro As Integer
col = 0
ro = 0

Set Rng1 = Selection

For Each cell In Rng1
  cell.Activate
  If col = 0 Then
     col = ActiveCell.Column
     ro = ActiveCell.Row
  End If
  op = op & cell & " "
Next cell

Cells(ro, col).Value = Trim(op)

End Sub

clear Python IDLE

import os

os.system('clear') #for Mac or Linux

os.system('cls') #for Windows

Taken from:

http://bytes.com/topic/python/answers/39943-screen-clear-question

python - translate and maketrans

>>> mystring='these'
>>> string.maketrans('ts','75')
'\x00\x01\x02\x03\x04\x05\x06\x07\x08\t\n\x0b\x0c\r\x0e\x0f\x10\x11\x12\x13\x14\
x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f !"#$%&\'()*+,-./0123456789:;<=>?@ABC
DEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqr57uvwxyz{|}~\x7f\x80\x81\x82\x83
\x84\x85\x86\x87\x88\x89\x8a\x8b\x8c\x8d\x8e\x8f\x90\x91\x92\x93\x94\x95\x96\x97
\x98\x99\x9a\x9b\x9c\x9d\x9e\x9f\xa0\xa1\xa2\xa3\xa4\xa5\xa6\xa7\xa8\xa9\xaa\xab
\xac\xad\xae\xaf\xb0\xb1\xb2\xb3\xb4\xb5\xb6\xb7\xb8\xb9\xba\xbb\xbc\xbd\xbe\xbf
\xc0\xc1\xc2\xc3\xc4\xc5\xc6\xc7\xc8\xc9\xca\xcb\xcc\xcd\xce\xcf\xd0\xd1\xd2\xd3
\xd4\xd5\xd6\xd7\xd8\xd9\xda\xdb\xdc\xdd\xde\xdf\xe0\xe1\xe2\xe3\xe4\xe5\xe6\xe7
\xe8\xe9\xea\xeb\xec\xed\xee\xef\xf0\xf1\xf2\xf3\xf4\xf5\xf6\xf7\xf8\xf9\xfa\xfb
\xfc\xfd\xfe\xff'
>>> transtbl=string.maketrans('ts','75')
>>>
>>> mystring
'these'
>>> mystring.translate(transtbl)
'7he5e'
>>>
>>>
>>> mystring
'these'
>>> mystring.translate(None,'ts')
'hee'
>>>

To translate mystring we need a translate table which has to be 256 bytes long. So we will use maketrans to cook up that table for us.

syntax: string.maketrans("From","to")

Just use this table in translate function.

syntax: mystringhere.translate("translation table")

Also, translate can be used without a translation table. If we give translation table as "None" and then provide optional list, these listed characters will be deleted.

The latter way of translate can come handy if you want to check if an incoming string contains numbers.

e.g.

>>> mystring='ab1234'
>>> if len(mystring.translate(None,'0123456789')) < len(mystring) :
... print 'input string contains numbers'
...
input string contains numbers

#

vi multiple lines ; repeat last commands

To join multiple lines in vi, use 5,9j! in cmd mode.
We know that J (note uppercase) on a line joins it with the next line. "!" preserves whitespace between the lines but it didn't in ksh shell.

To apply last used substitute command through out the file:
e.g. %s/this/that/g

& to repeat the last used substitution for the first occurrence on the current line
&g to change all on the current line
%&g for entire file

Use . to repeat the last insert command. It inserts the last few inserted words/lines after the cursor.